hollalinux
/
linux-sg2042
mirror of https://github.com/sophgo/linux-riscv.git
1
0
Fork 0
Code Issues Packages Projects Releases Wiki Activity

USB: ftdi_sio: added CS5 quirk for broken smartcard readers 

Genuine FTDI chips support only CS7/8. A previous fix in commit
8704211f65 ("USB: ftdi_sio: fixed handling of unsupported CSIZE
setting") enforced this limitation and reported it back to userspace.

However, certain types of smartcard readers depend on specific
driver behaviour that requests 0 data bits (not 5) to change into a
different operating mode if CS5 has been set.

This patch reenables this behaviour for all FTDI devices.

Tagged to be added to stable, because it affects a lot of users of
embedded systems which rely on these readers to work properly.

Cc: stable <stable@vger.kernel.org>
Reported-by: Heinrich Siebmanns <H.Siebmanns@t-online.de>
Tested-by: Heinrich Siebmanns <H.Siebmanns@t-online.de>
Signed-off-by: Colin Leitner <colin.leitner@gmail.com>
Signed-off-by: Johan Hovold <jhovold@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Colin Leitner 2014-01-06 21:33:54 +01:00 committed by Greg Kroah-Hartman
parent 30666249ea
commit c1f15196ac
1 changed files with 15 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

17
drivers/usb/serial/ftdi_sio.c
View File

@ -2121,10 +2121,20 @@ static void ftdi_set_termios(struct tty_struct *tty,
}
/*
* All FTDI UART chips are limited to CS7/8. We won't pretend to
* All FTDI UART chips are limited to CS7/8. We shouldn't pretend to
* support CS5/6 and revert the CSIZE setting instead.
*
* CS5 however is used to control some smartcard readers which abuse
* this limitation to switch modes. Original FTDI chips fall back to
* eight data bits.
*
* TODO: Implement a quirk to only allow this with mentioned
* readers. One I know of (Argolis Smartreader V1)
* returns "USB smartcard server" as iInterface string.
* The vendor didn't bother with a custom VID/PID of
* course.
*/
if ((C_CSIZE(tty) != CS8) && (C_CSIZE(tty) != CS7)) {
if (C_CSIZE(tty) == CS6) {
dev_warn(ddev, "requested CSIZE setting not supported\n");
termios->c_cflag &= ~CSIZE;
@ -2171,6 +2181,9 @@ no_skip:
urb_value |= FTDI_SIO_SET_DATA_PARITY_NONE;
}
switch (cflag & CSIZE) {
case CS5:
dev_dbg(ddev, "Setting CS5 quirk\n");
break;
case CS7:
urb_value |= 7;
dev_dbg(ddev, "Setting CS7\n");